Take a Fostex T50RP
semi-open dynamic studio headphone, which
you can pick up on Amazon for $126, breath on it as described in many web blogs
for tweakers, and there you have a serious bit of kit. At the heart of the
headphone is its isodynamic (or orthodynamic or planar magnetic) driver.

According to WikiphoniaIsodynamic drive headphones have drivers with flexible plastic
film diaphragms into which a flat voice coil (spiral or serpentine in shape--see
photos below) is embedded or glued on for even distribution of the drive force.
That is, the diaphragm is driven more or less equally over its entire surface at
once, obviating the need to make the diaphragm rigid so that it can therefore be
as lightweight and agile and non-resonant as possible. Isodynamic diaphragms are
either lightly tensioned or corrugated to supply restoring force. Magnetic
assemblies (bar magnets or perforated disc magnets) on both sides of the
diaphragm supply the magnetic field against which the voice coil's varying
magnetic field reacts, which makes the diaphragm vibrate. Isodynamic diaphragms
are more massive than electrostatic diaphragms, but the equal-force drive
principle allows them to move very quickly and in a coherent, uniform way, so
provided there is sufficient mechanical damping, an isodynamic headphone gives
excellent transient response and a sound quality not unlike that of an
electrostatic.

Recognizing that the drivers are not performing to their
highest potential, tweakers have made many modifications to improve damping,
bass response, treble extension, comfort, cabling and aesthetics. Dan Clark,
founder of MrSpeakers, can do all this for you for a price. He'll be happy to
sell you his Mad Dog with leather Alpha Pads and comfort strap for a modest
$299.99, to which you must add a headphone cable of your choice. Pulling out all
the stops Dan gives you the Alpha Dog at just $599.99. This is the animal we are
examining today, and not only is it almost unrecognizable as a Fostex
derivative; it also comes with a 6' cable (terminated your way) and a bag of
tricks to let you tweak the sound still further. Oh yes, did I mention the
casing is produced on a 3D printer? What's that about?

The Alpha Dog comes in a Claret red or Midnight Black
automotive gloss paint finish. The test pair had the red finish, which looks
great. Let's take a look at the before and after images

.

Dan was using a 3D printer to prototype various cup designs.
During the process he found he could build a cup design that regular injection
molding just couldn't achieve. So that's where the first 3D printed
headphone design comes from. The shell (a.k.a. Super-Cup) is a dual skinned device
with lattice bracing between the inner and outer skin. It combines light weight
with high rigidity, intended to increase isolation, expand the soundstage,
smooth the frequency response and offer a faster and more tuneful bass. Dan set
out to achieve the open soundstage of a open backed design with the isolation
from external noise and the bass response of a closed cup design, squaring a
circle that has eluded all comers. Has he succeeded? You'll have to read on.

About MrSpeakers

MrSpeakers was founded with a simple goal in mind: great
headphone products at affordable prices. At MrSpeakers, we believe audiophile
performance should not require stratospheric prices, and as such we strive to
deliver incredible performance and high value for each and every product we
deliver. No fancy packaging, no expensive upgrades or components that don't
add real value. No snake-oil.

MrSpeakers was founded by Dan Clark, an electrical engineer
who has been working in and around the high-end audio market for more than
twenty years, and who has designed a number of commercial and custom loudspeaker
solutions, including the highly-regarded and award winning Platinum Audio
speakers from the late 1990′s.

One of the most remarkable features of the Alpha Dog is that
while Dan has tuned it for a flat frequency response, he recognizes that your
ears may prefer more bass, or a sweeter treble. So his Very-Bass tuning system
includes a set screw with which you can increase or reduce the bass response
below 150Hz – one that you are meant to set and forget.

And there are two adjustments for the treble. First some Blue
Monkey Dots (one or two per cup) you can affix to the drivers to smooth out the
frequency response. Then some felt tuning discs pads which can reduce the level
of the treble above 4kHz by about 1 dB each for those so inclined. I liked the
phones best with two dots per side but no felt tuning pads, and I left the bass
vent at its factory setting.

It is immediately obvious that this pair is performing at a
level way above what you would expect at this price. My AKG K701 was clearly
outclassed on every selection. The Alpha Dog threw a bigger warmer deeper
soundstage, making the AKG sound rather analytical.

I needed the best quality hardware to feed the listening tests
and a top notch recording to set the challenge. Luckily this week my EMM Labs
XDS1 SACD Player came back from a major upgrade and a new DSD recording Of
Dvorak's Eighth Symphony on the Reference Recordings label [FR710SACD] arrived
in the post. I fed the output XDS1 through Nordost Vahalla interconnects into a
Graham Slee Solo Ultralinear headphone amplifier and after calibrating the small differences
in sensitivities between them, auditioned the Alpha Dog against the K701 and my
reference Sennheiser HD800 with a Cardas Clear headphone cable.

First the recording itself. It's not perfect – one can
occasionally hear very low level background noise (traffic, breathing etc) –
but this is a live recording from the Pittsburgh Symphony Orchestra under its
conductor Manfred Honeck, and it's a beauty. Not dramatic or over mic'ed, but
beautifully balanced and atmospheric. The Alpha Dog reproduced this in a most
musical and satisfying manner. The orchestra sounded very well balanced with
plenty of bravura passages handled without distortion and lots of detail in the
most delicate moments. Image size was impressive and instrumental color there in
abundance. The Sennheiser / Cardas combination is a reference for good reason,
and it is clearly in a different league. It reveals more texture on the strings,
has a greater ease and openness about it, and offers the widest range of
dynamics. Its overall balance is very similar to the Alpha Dog, but its bass is
even more articulated and the treble seems to go on forever without sounding
etched. But we are talking around triple the price. The AKG sounds less natural
and lacking richness in the middle and lower registers compared to the other
two. It has detail galore but a less three dimensional and more compact image.
Neither the Alpha Dog nor the AKG could quite capture the tonal quality of the
solo horn or the composition of the strings that follow in the fourth movement,
but the Alpha Dog has more bite and realism than the AKG on the string tone and
is just as convincing as the Sennheiser even if doesn't tell the complete
story.

I had a lot of fun with my exploration of the Alpha Dog,
pulling out one recording after another. It never disappointed me, and in fact I
can say that from genre to genre and on music of all scales, the relative
performance of the three units was consistent. The Alpha Dog was always closer
to the Sennheiser than the AKG to it, and unless you played a track A/B you'd
never know you were giving anything up.

Here is a way to get into the high end of headphone listening
on a limited budget. You'll need a good headphone amplifier. Alpha Dogs are quite
demanding compared to most phones, and they needed a touch more juice than the
already fussy Sennheisers, but they are not as demanding as several other
isodynamic phones and I found them relatively forgiving. I have recommended the
Solo before and it is a good match here. The Solo's volume control may need
cranking up to the 3 o'clock position but Graham Slee tells me they are
designed to work this way and will not be under strain in that position, which
is not true for many other vendors.

I'm very impressed with the Alpha Dog. It's very
comfortable for a closed phone, with its soft padding and adjustments, but it
may prove hot under prolonged listening, and it presses in on the head more than
the HD800 or K701. It's well finished and I am very happy to see the range of
user adjustments to the frequency extremes that are included in the package.
Another plus is that a simple but effective headphone stand is also provided.

By building such an excellent all round headphones and pricing
it so modestly, Dan Clark has knocked one out of the park.

Manufacturer's CommentsHi Phil,

Thank you for the kind review! We're really glad you enjoyed
the Alpha's sound and comfort both in an absolute and a relative sense. Our goal
was to make a great sounding, comfortable yet affordable headphone.

We did note your concern about clamp force. Fortunately, the
Mad Dog and Alpha Dog are easily adjusted to increase or reduce clamp, or even
to change the width and angle of the risers. You can see how easy it is to
adjust in
this video. Loosening
the clamp is exactly the opposite motion, and it's safe and easy to adjust.